Heavy Duty Pavement Design
-
Upload
paveman -
Category
Technology
-
view
8.053 -
download
5
description
Transcript of Heavy Duty Pavement Design
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Heavy Duty Pavement DesignDesign
Dr Wei LiuDr Wei Liu
Senior EngineerSenior Engineer
Fugro-PMS Ltd, New ZealandFugro-PMS Ltd, New Zealand
Presentation to Prologis ChinaPresentation to Prologis China
Presentation OverviewPresentation Overview
IntroductionIntroduction Pavement Design Method for Heavy Pavement Design Method for Heavy
Duty PavementDuty Pavement Case StudyCase Study
Presentation to Prologis ChinaPresentation to Prologis China
IntroductionIntroduction Pavement is the layered structure on Pavement is the layered structure on
which vehicles will travel. It's purpose is which vehicles will travel. It's purpose is two fold, to provide comfortable and two fold, to provide comfortable and durable surface for the vehicles and to durable surface for the vehicles and to reduce stresses to the underlying soils. reduce stresses to the underlying soils.
Presentation to Prologis ChinaPresentation to Prologis China
IntroductionIntroduction There are two types of There are two types of
pavement frequently in use pavement frequently in use throughout the world :throughout the world :
• FlexibleFlexible - pavements with - pavements with a bitumen bonded surface.a bitumen bonded surface.
• RigidRigid - Pavements with a - Pavements with a concrete slab surface which concrete slab surface which can be un-reinforced, joint can be un-reinforced, joint reinforced or continuously reinforced or continuously reinforced.reinforced.
Presentation to Prologis ChinaPresentation to Prologis China
IntroductionIntroduction
What is Heavy Duty Pavements?What is Heavy Duty Pavements?• Pavements subjected to the extremely Pavements subjected to the extremely
heavy wheel loads associated with heavy wheel loads associated with freight handling vehicles in industrial freight handling vehicles in industrial facilities, such as container terminals facilities, such as container terminals and warehouses and warehouses
Presentation to Prologis ChinaPresentation to Prologis China
IntroductionIntroduction
Common pavement distresses:Common pavement distresses:• Rutting: Rutting: a result of heavy, slow moving traffic.
Common in warm areas. Permanent deformation in the wheel paths .
• Fatigue Cracking: With every passing of a vehicle, pavement layer bends under loading. Over time, layer will crack; propagation of cracks upward eventually reaches the surface. Fatigue cracking occurs as individual cracks interconnect.
Presentation to Prologis ChinaPresentation to Prologis China
IntrodcutionIntrodcution
What is pavement design?What is pavement design?• The goal of pavement design is to The goal of pavement design is to
determine the number, material determine the number, material composition and thickness of the composition and thickness of the different layers within a pavement different layers within a pavement structure required to accommodate a structure required to accommodate a given loading regime. given loading regime.
Presentation to Prologis ChinaPresentation to Prologis China
IntroductionIntroduction
Special Issues in heavy duty Special Issues in heavy duty pavement designpavement design• Slow moving or static traffic loadSlow moving or static traffic load• Ultra high load magnitudeUltra high load magnitude• Load WanderingLoad Wandering
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Design PrincipleDesign Principle Empirical Vs Mechanistic Empirical Vs Mechanistic Material CharacterizationMaterial Characterization Load CharacterizationLoad Characterization Pavement Response ModelPavement Response Model Failure ModelsFailure Models
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Design PrincipleDesign Principle• Minimize critical vertical stress in lower Minimize critical vertical stress in lower
layers that result inlayers that result in RuttingRutting
• Minimize critical tensile stresses in Minimize critical tensile stresses in upper layers that result inupper layers that result in
Fatigue crackingFatigue cracking
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Empirical Vs MechanisticEmpirical Vs Mechanistic• Empirical Methods are basedEmpirical Methods are based on the results of on the results of
experiments or experience. experiments or experience. Advantage: Simpler approachAdvantage: Simpler approach Disadvantage: Disadvantage: Cannot cope with novel materials or pavement Cannot cope with novel materials or pavement
structures.structures.
It is “like driving a car by only looking It is “like driving a car by only looking in the rear vision mirror, you could only be sure where in the rear vision mirror, you could only be sure where you had been, but not where you were going” you had been, but not where you were going”
– – Geoff Youdale, Chairman, Austroads Geoff Youdale, Chairman, Austroads
Pavement Research GroupPavement Research Group
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Empirical Vs MechanisticEmpirical Vs Mechanistic• Mechanistic method applies the physics Mechanistic method applies the physics to determine:to determine:
The reaction of structures to loading. The reaction of structures to loading. Distribution of vehicle loads to the underlying soil layers.Distribution of vehicle loads to the underlying soil layers. Need fundamental properties of the materials, pavement Need fundamental properties of the materials, pavement
thicknesses, load characteristics. thicknesses, load characteristics.
Traffic
Climatic data
Design & material property
parameters
Pavement response models ()
Incremental fatigue damage models
Transfer functions
Performance prediction models (rutting, % cracks, etc….)
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Empirical Vs MechanisticEmpirical Vs Mechanistic• Advantages of mechanistic methods:Advantages of mechanistic methods:
Design for new load types (such as super single tires).Design for new load types (such as super single tires). Design with new materials (such as Soilfix stabilized Design with new materials (such as Soilfix stabilized
material).material). Improve reliability of predicting performance.Improve reliability of predicting performance. Using performance related material properties.Using performance related material properties. Use of environmental effects.Use of environmental effects.
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Material CharacterizationMaterial Characterization• SubgradeSubgrade
Characterized by strength and/or stiffness Characterized by strength and/or stiffness • California Bearing Ratio (CBR)California Bearing Ratio (CBR)
Measures shearing resistanceMeasures shearing resistance Units: percentUnits: percent Typical values: 0 to 20Typical values: 0 to 20
• Resilient Modulus (MResilient Modulus (MRR)) Measures stress-strain relationshipMeasures stress-strain relationship Units: MPaUnits: MPa Typical values: 30 to 300 MPaTypical values: 30 to 300 MPa
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Material CharacterizationMaterial Characterization• SubgradeSubgrade
Effect of Moisture ContentEffect of Moisture Content
020406080
100120140160180200
0 5 10 15 20
Moisture Content, %
Mo
du
lus,
MP
a
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Material Material CharacterizationCharacterization• Subbase and Subbase and
RoadbaseRoadbase Elastic Modulus Elastic Modulus E Poisson’s RatioPoisson’s Ratio
Definitions of E and .
D/2
l
l
l = l/l
t = D/D
E =
= l/t
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Material CharacterizationMaterial Characterization• Surface LayerSurface Layer
Asphalt MixAsphalt Mix• Dynamic Modulus E* (Dynamic Modulus E* (Witczak Equation)Witczak Equation)log . . . ( ) . .
.. . . . ( ) .
( . ` . log( ) . log( ))
E V
V
V V e
a
beff
beff af
1249937 0 29232 0 001767 0 002841 0 058097
08022083871977 0 0021 0 003958 0 000017 0 005470
1
200 2002
4
4 38 382
340 6033 3 0 313351 0 393532
• bitumen viscosity
• loading frequency
• air voids
• effective bitumen content
• cum. % retained on 19-mm sieve
• cum. % retained on 9.5-mm sieve
• cum. % retained on 4.76-mm sieve
• % passing the 0.075-mm sieve
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Material CharacterizationMaterial Characterization• Surface LayerSurface Layer
Asphalt MixAsphalt Mix
10
100
1000
10000
-20 -10 0 10 20 30 40 50
Temperature, C
Mo
du
lus,
MP
a
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Material CharacterizationMaterial Characterization• Surface LayerSurface Layer
Porland Cement ConcretePorland Cement Concrete• Elastic ModulusElastic Modulus• Flexural strengthFlexural strength
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Load CharacterizationLoad Characterization• Pavement damagePavement damage
Miner’s lawMiner’s law
• CharacterizationCharacterization SpectrumSpectrum Expressed as a fraction of a standard load Expressed as a fraction of a standard load
• Pavement lifePavement life Expression of how much load repetitions can Expression of how much load repetitions can
be endured before unacceptable be endured before unacceptable serviceabilityserviceability
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Pavement Response ModelPavement Response Model• Layered Elastic AnalysisLayered Elastic Analysis
Each layer is homogenous, isotropic, linearly Each layer is homogenous, isotropic, linearly elastic (E,elastic (E,))
Each layer is weightlessEach layer is weightless Infinite in x, y, finite in z directionInfinite in x, y, finite in z direction Uniform pressure applied over a circular Uniform pressure applied over a circular
areaarea Continuity at layer interfacesContinuity at layer interfaces
• Same: vertical & shear stress Same: vertical & shear stress vertical and radial displacementvertical and radial displacement
Presentation to Prologis ChinaPresentation to Prologis China
Layer 1HMA
E1
Layer 3Subgrade Soil
E3
h1
h2
No bottom boundary, assume soil goes on infinitely.
Nohorizontalboundary, assumelayersextendinfinitely.
Tire has a total load P, spread over a circulararea with a radius of a, resulting in a contactpressure of p.
PavementReactions
Deflection ()
Tensile Strain (t)
Compressive Strain (Compressive Strain (vv))
Layered Elastic Model Representation of a Pavement
Layer 2Granular
BaseE2
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Pavement Response ModelPavement Response Model• Critical Pavement Responses and LocationsCritical Pavement Responses and Locations
LocationLocation ResponseResponse
Pavement surfacePavement surface Deflection (vertical)Deflection (vertical)
Bottom of HMA layer(s)Bottom of HMA layer(s) Horizontal tensile strainHorizontal tensile strain
Top of intermediate layer Top of intermediate layer (base or subbase)(base or subbase)
Vertical compressive Vertical compressive strainstrain
Top of subgradeTop of subgrade Vertical compressive Vertical compressive strainstrain
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Failure ModelsFailure Models• Fatigue CrackingFatigue Cracking
allowable number of load repetitions related to tensile allowable number of load repetitions related to tensile strain at bottom of asphalt layerstrain at bottom of asphalt layer
AI & Shell design methods -- allowable load repetitions AI & Shell design methods -- allowable load repetitions related to tensile strain and modulusrelated to tensile strain and modulus
NNff = f = f11((tt))-f2-f2(E(E11))-f3-f3
Modulus effect is small (f3 is smaller than f2)Modulus effect is small (f3 is smaller than f2) Several models that include only strain : Several models that include only strain : NNff = f = f11((tt))-f2-f2
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Failure ModelsFailure Models• RuttingRutting
2 procedures to limit rutting2 procedures to limit rutting• limit vertical compressive strain on top of subgradelimit vertical compressive strain on top of subgrade• limit total accumulated permanent deformationlimit total accumulated permanent deformation
AI and Shell design -- allowable number of load AI and Shell design -- allowable number of load repetitions to limit rutting related to vertical repetitions to limit rutting related to vertical compressive strain on top of subgrade compressive strain on top of subgrade
Form (can be used for all materials):Form (can be used for all materials):
pp = a( = a())bb(N)(N)1-m1-m
Presentation to Prologis ChinaPresentation to Prologis China
Heavy Duty Pavement Design Heavy Duty Pavement Design MethodMethod
Failure ModelsFailure Models• Miner’s HypothesisMiner’s Hypothesis
Provides the ability to sum damage for a Provides the ability to sum damage for a specific distress typespecific distress type
D = D = n nii/N/Ni i 1.0 1.0
where nwhere ni i = actual number of repetitions = actual number of repetitions for load i for load i
NNi i = allowable number of repetitions = allowable number of repetitions for load i for load i
Presentation to Prologis ChinaPresentation to Prologis China
Case StudyCase Study
Design Conditions:Design Conditions:• A concrete pavement for a heavy duty A concrete pavement for a heavy duty
industrial hardstand with a total industrial hardstand with a total repetition of 182,5000 with a 10 ton axle repetition of 182,5000 with a 10 ton axle load for a period of 5 years. load for a period of 5 years.
• Roadbase is the Soilfix Stabilized Roadbase is the Soilfix Stabilized Aggregate Aggregate
Presentation to Prologis ChinaPresentation to Prologis China
Case StudyCase Study
Design Inputs:Design Inputs:
LayerLayer MaterialMaterial Thickness Thickness (mm)(mm)
Modulus Modulus (MPa)(MPa)
Poisson’s Poisson’s RatioRatio
11 Porland Cement Porland Cement ConcreteConcrete
200200 30003000 0.150.15
22 Soilfix Stabilized Soilfix Stabilized AggrageAggrage
300300 68906890 0.20.2
33 Compact SoilCompact Soil 0.40.4
Presentation to Prologis ChinaPresentation to Prologis China
Case StudyCase Study
Pavement Response CalculationsPavement Response Calculations• Critical Stresses in Pavement StructureCritical Stresses in Pavement Structure
Loc# Layer
Coordinates (mm) Normal Stress (kPa) Shear Stress (kPa)
X Y Z X Y Z YZ XZ XY
1 1 0 0 200 -1970.76 -2461.34350.1
9 0 0 0
2 1 171.5 0 200 -2207.53 -2660.59 407 0 0 0
3 3 0 0 500 35.1 35.28 37.04 0 0 0
4 3 171.5 0 500 36.51 36.62 38.49 0 0 0
Presentation to Prologis ChinaPresentation to Prologis China
Case StudyCase Study
Pavement Response CalculationsPavement Response Calculations• Critical Strains and Displacements in Pavement Critical Strains and Displacements in Pavement
StructureStructure
Loc Layer
Coordinates (mm) Normal MicroStrainDisplacement (micrometer)
X Y Z X Y Z X Y Z
1 1 0 0 200 -82.7 -110.91 50.75 15.3 0 1067.43
2 1 171.5 0 200 -93.47 -119.53 56.86 0 0 1081.58
3 3 0 0 500 42.68 46.84 89.52 -7.59 0 1059.58
4 3 171.5 0 500 45.1 47.91 93.01 0 0 1072.66
Presentation to Prologis ChinaPresentation to Prologis China
Case StudyCase Study Pavement Life PredictionPavement Life Prediction
• Fatigue Cracking ModelFatigue Cracking Model
• Rutting ModelRutting Model
• Results:Results:
Fatigue Rutting
Applied Numbers 1825000 1825000
Allowed Numbers 1.54E+07 2.41E+08
Damage Factor 0.12 0.01
MRN f
61.1761.17log
87.3
16 110
vrN
Presentation to Prologis ChinaPresentation to Prologis China
Thank you!